Electrical switch



L. A. M. PHELAN ELECTRICAL SWITCH Filed Dec.

Oct. 17, 1933.

a Mm NW. 7

Patented oct. 17, 1933 1,931,238

1,931,238 ELECTRICAL s'wrrcn- Louis A. M. Phelan, Elkhart,-Ind., assignor, by mesne assignments, to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a compration of Delaware Application December 22, 1926 Serial No. 156,345

18 Claims. (Cl. 200-139) This invention relates to an electric switch and acteristic features of this invention, in which has special reference to an electric switch drawing:

actuated by a heat responsive element. Figure 1 is a side elevational view of the device More particularly this invention relates to an as installed onv a hot riser; electric switch actuated by a heat responsive ele- Fig. 2 is a rear sectional view taken on the 60 ment and having means whereby a substantially line 2-2 of Fig. 1; horizontal or minimum heat gradient is estab- Fig. 3 is a sectional view taken on the line 3--3 iished between a radiant point and said heat reof Fig. 2; and sponsive element, Fig. 4 is a front `Sectional View taken 0n the y The term radiant point as used herein may line 4 4 of Fig. 1. 35

be dened as the point from which rays of heat Referring more particularly to the drawing, proceed and is the object or thing .to which the wherein this invention is illustrated, the device electric switch is applied. Also, the term heat will be hereinafter described as provided with a gradient as used herein may be defined as the thermostatic coil having a. liquid 01 mercury C011- rate at which the heat changes in value, and tactor switch mounted thereon, the energy ex- 70 therefore, a minimum heat gradient between a pended by the coil at a predetermined temperaradiant point and a heat responsive element may ture varying the position of said switch in such be interpreted as a minimum dissipation of heat manner as to open or close the circuit therein. between the heat responsive element of an electric It isto be understood, however, that any type switch and the object to which said switch is of heat responsive element may be used that will 75 applied, provide an actuating force for an electric switch- This invention will be hereinafter described in ing mechanism for opening and closing the elecassociation with a heating system wherein said tric circuit as the thermostat or heat responsive device is applied to the exterior of a hot riser of a element expands and contracts by reason of temhot water plant. In this connection the device perature changes that may influence it. 80 utilizes the temperature lag between the riser The electric switch comprises a shell or casing upon which the device is installed and the hot 10, preferably of an insulating material, having water' tank. a glass wall 11 mounted on the face side of said To be more explicit, it may be assumed that the casing, said glass being held in position by a rim device is used for controlling a burner in a heat- 12 suitably secured to the shell 10 as by means 86 ing system and is installed on the hot riser leadof screws 13. The rear of said shell 10 is ening'from a boiler to a hot water tank. When the closed by meansv of a metal plate 14 having a burner is in operation, the hot riser is hotter than plurality of lugs 15, `preferably integral therethe hot water tank. When the burner is idle, with, and extending into said shell to be secured the hot riser is cooler than the hot water tank. thereto by means of screws 16. An outlet box 17. 90 This temperature lag has the effect of sensitizing provided with lugs 18, is attached to the shell 10 the thermal unit in the device thus causing an by means of screws 16 extending through said actuation thereof for controlling the burner so lugs 18 r.and shell 10 and into said lugs 15. that the temperature of the hot water tank is The switching mechanism may preferably com- 40 practically invariable. priseA a cylindrical and elongated tube 19 made 95 In order to control the burner efficiently so of glass and serving to house a'pair of electrodes that the temperature of the water in the hot water or contact-making members 20 and 21, said lattank is practically constant, it is necessary that ter members being located at one end of said tube substantially the entire aforementioned temand adapted to be bridged by a body of electrical perature lagbe recorded by-,the thermal unit for current-conducting fluid, such as mercury 22, 10d actuating the controlling means and, therefore, which iiuid is likewise disposed in said tube. It this invention has particular reference to an will be apparent from the drawings that if the electrical switch having means for minimizingv tube 19 should be tilted in the proper direction,

the amount of heat lost in the transmission therethe body of mercury 22 will 110W toward the elecof from the riser upon which said switch is trodes 20 and 2l,thus bridging the electrodes and 105 mounted to the thermal unit within said switch. vplacing them in .electrical contacting relation Other objects will be apparent from the dewith each other. Thistube 19, housing theaforescription and drawing forming a part of this mentioned elements, will hereinafter be referred specification to which reference may now be had to as a mercury or liquid contacter. v for a more complete understandingof the char- The tube 19 is mounted on the inner end of a 110 spiral thermostatic element 23 by means of a detachable band 24, which latter is suitably secured to a stud 25 adjustably mounted in a collar 26, said collar being secured to said inner end of said element 23 by suitable means such as a screw 27. The spiral element 23 is supported in turn by means of its outer end being secured to a cap or housing 28 by a screw or other suitable means, said cap having an aperture 28a through which the collar 26 extends.

As it is desirable to have the device close the circuit at various temperatures, the cap 28 is rotatably mounted on the plate 14 by means of the flange 29 engaging a plurality of lugs 30 extending from plate 14 and disposed around the periphery of said flange 29. Aregulating arm 31, preferably integral with said flange, extends from the flange and through an elongated slot 32, said arm acting to adjust the angular position of the switching mechanism and also serving to hold the cap in its position against the wall 14. In

my novel device it may also be advantageous to provide any suitable additional means on the shell 10 and engaging the cap 28 for urging the cap against the wall 14, but in order to avoid confusion of the various parts, such means are not shown and form no part of my invention.

In order to regulatethe switching mechanism so that it will close the circuit at various temperatures, the regulating arm 31 is moved in the proper direction toward the desired position, whereafter the spiral element is rotated by thermal conditions and changed to circuit closing or opening position as thecase may be. For example, if it is desired to have the device close the circuit at a temperature of '10 instead of 65,

the regulating arm 31 is adjusted so that the v angular position of the contactor tube is changed whereby the energy induced by the expansion of the coil at' 70 will be sufficient to continue the rotation of the tube 19 to circuit closing position.

'I'he switch is mounted on the hot riser or pipe 33, preferably by means of two metal bands 34 engaging ears 35, which latter extend` from plate 14. In this manner, the metal plate 14 is held in a contacting relation with the pipe 33 which causes the former to be heated. Inasmuch as the flange 29 of the cap 28 has a substantial contact with the plate 14, heat is thereby transmitted to said flange from plate 14 and thence throughout the entire surface of the cap. As a result of this transmission of heat throughout the plate 14 and the cap 28, the thermostatic element 23, which is disposed between the plate and cap, receives an even distribution of heat on all sides thereof. It is essential, of course," that the plate 14 and cap 28 are of a character having a high heat conductivity, such for instance as aluminum.

In order to enhance the thermal conductivity to the bimetallic element or thermostatic element 23, it may be desirable to dispose a semiliquid material in the cap 28 to surround the coils of the element 23. The substance of this semi-liquid material may be of cosmolinev or petroleum jelly, which, besides being good thermal conductors, also act to keep the moving parts oi' the instrument waterproofed and free from moisture. It is preferable that this body of petroleum jelly or other substance should have a `point of solidiiication lower than that to any temperature to which the instrument may be subjected so as to minimize the friction in the operation of the element 23.

It will be readily apparent that the aforementioned structure provides means whereby the loss of heat, which is radiated from the pipe 33 to effect the thermal unit 23, is practically negligible, and moreover, that substantially the entire heat radiation is transmitted to all sides of the thermal unit, thereby providing as practical and efficient a structure as though the thermal unit were immersed in the heating content itself.

It is to be understood, however, that the thermal unit shown in the drawing is merely for illustrative purposes, and that it may be desirable to provide a conical or helical spiral element instead of the simple spiral shown in this device. Furthermore, a simple coil element, or any heat responsive element, may be used as the actuating element, it being necessary only to redesign the cap 28 to conform to the contour of the element thus used. It is also to be understood that the device is not to be limited to the switching mechanism herein described, since any switching mechanism which may be controlled by a thermal unit may vbe readily employed, however, many advantages reside in a mercury contactor tube.

As a result Voi? this invention, there exists a substantially horizontal heat gradient between the radiant point and the thermal unit, and while a single embodiment of this invention is herein shown anddescribed, it is to be understood, nevertheless, that this invention is not to be limited tothat particular structure since various modifications will be apparent to one skilled in the art without departing from the spirit and scope of this invention, and therefore, this invention is to be limited only by the scope of the appended claims and the prior art.

I claim:

1.- An electrical device comprising a heat conducting plate of relatively high thermal conductivity for contact with a radiant point, a heat conducting housing of relatively high thermal conductivity rotatably mounted on said plate, a flange on said housing for making a substantial surface contact with said plate, thermal responsive means disposed within said housing and adjacent said plate whereby a minimum of heat gradient is established between a radiant point and said thermal responsive means, one end of said thermal means being fixed to said housing, and an electrical switch mounted on the opposite end of said thermal responsive means, and an arm extending from said flange for rotating said housing to adjust the angular position of said switch.

2. A thermally actuated electric switch comprising a heat conducting plate adapted to contact with a heat radiant point, a thermal responsive element disposed adjacent to said plate, an adjustable heat conducting casing enclosing said thermal responsive element and in close thermal relation to said heat conducting plate, an electrical switching -means exterior of said casing, and means connectingv said switching means and said thermal responsive element whereby the former may respond to the thermal conditions of the latter, said switching means being adjustable in unison with said casing.

3. A thermally actuated electric switch comprising a heat conducting plate adapted to contact with a heat radiant point, a thermal responsive element disposed adjacent to said plate, a heat conducting casing enclosing said thermal responsive element and in close thermal relation to said heat conducting plate -and adjustable relatively thereto1 a mercury contactor switch exterior of said casing, and means connecting said contactor switchwith said thermal responsive element whereby operation of the former is controlled in accordance with the thermal conditions of the latter.

4. A thermally actuated electric switch comprising a heat conducting plate adapted to contact with a heat radiant point, a heat responsive element disposed adjacent thereto, a heat conducting casing enclosing said heat responsive element and in close thermal relation to said plate but adjustable relatively thereto, said heat responsive element being secured to said casing so as to move in unison therewith, electrical switching means exterior of said casing, and means'connecting said switching means and said thermal responsive element whereby the former may be controlled by the latter.

5. A thermally actuated electric switch comprising a heatconducting plate adapted to contact with a heat radiant point, a bimetallic element disposed in close proximity to said plate, a heat conducting casing enclosing said bimetallic element and disposed in close thermal relation to said plate but adjustable relatively thereto, said bimetallc element being secured to said casing so as to move in unison therewith, electrical switching means exterior of said casing and spaced therefrom a substantial. distance, and means connecting said switching means and said thermal responsive element whereby the operation of the former may be controlled by the latter.

6. A thermally actuated electric switch comprising a heat conducting plate adapted to contact with a heat radiant point, a heat responsive element disposed in close thermal relation to said plate, a heat conducting casing enclosing said heat responsive element and disposed iny close thermal relation to said plate and said element, an electric switching means exterior of said heat conducting casing, means connecting said switching means and said heat responsive element whereby the operation of the former may be controlled by the latter, a housing enclosing said switching means, said -heat conducting casing and said heat responsive element, and means accessible exteriorly of said housing for adjustving the position of said heat Yresponsive element andswitching means.

7. A thermally actuated electric switch comprising a heat conducting plate adapted to contact with a heat radiant point, a coiled bimetallic element disposed in close thermal relation to saidk plate, a heat conducting casing enclosing said bimetallic element and inv close thermal relation thereto and to` said plate, said casing'being adjustable relatively to said plate and said bimetallic element having one end secured to said casing so as to move in unison therewith, an electrical switching means exterior of said casing, and means connecting said switching means and the other end of said thermal responsive element.

8. A thermally actuated electric switch comprising a heat conducting plate adapted to contact with a heat radiant point, a coiled bimetal` lic element disposed in close thermal relation to said plate, a heat conducting casing enclosing said bimetallic element and in close thermal relation thereto and to said plate, said casing being adjustable relatively to said plate and said bimetallic element having one end secured to said casing so as to move in unison therewith, a mercury contactor exterior of said casing, and

means connecting said mercury contactor and the other end of said bimetallic element.

9. A thermally actuated electric switch comprising switching means, thermal responsive means for operating said switching means, a heat conducting plate of relatively high conductivity for contact with a radiant point and adapted to be attached thereto, and a heat conducting housing of relatively high thermal conductivity having a ange on said housing for making a sub.- stantial surface contact with said plate whereby a close 'thermal relation is established between said housing and said plate, said thermal means being disposed within said housing and adjacent said plate whereby a minimum of heat gradient exists between said radiant point and said thermal responsive means and said switchingk means being disposed exteriorly of said housing.

10. An electrical device comprising a heat consubstantial surface contact with said plate, ther` mal responsive means disposed within said housing and positioned adjacent to said plate whereby a minimum of heat gradient is established between the radiant point and said thermal responsive means, one end of said thermal means being iixed to said housing, an electrical contactor Wholly and tiltably supported upon the other end of said thermal responsive means, and an arm extending from said housing foradjusting the tilting angle of said contactor.

11. An electrical device comprising a'heat conducting plate for contact with a radiant point, a thermal responsive element positioned adjacent to said plate, a heat conducting housing movable relatively to said plate and enclosing said heat responsive element, a flange associated with said housing for making substantial surface contact with said plate, said housing and said plate establishing a minimum heat gradient between the radiant point and said thermal responsive means, said thermal responsive means being xed to said housing, electric switching means exterior of lsaid housing and actuated by said thermal responsive means, and means for adjusting said vhousing to control the operation of said switching means.

12. In'a thermostat, a casing, a thermal element whose position varies with change of temperature carried by said casing, an voscillatable mercury switch carried and controlled by said thermal element, and means for mounting said casing for movement to shift the position of the lthermal element to vary the relation of the mercury to the switch contacts.

g 13. In a thermostat, a casing, a thermal element whose position varies with change of temperature carried by said casing, an oscillatable mercury switch carried and controlled by said thermal element, and means for mountingv said casing for movement to'shift the position of the thermal element to vary the relation of the mercury to the switch contacts, said mercury switch being outside said casing.

14. In a thermostat, a casing, a thermal element whose position varies with change of temperature carried by said casing, an oscillatable mercury switch carried and controlled by said thermal element, means for mounting said casing for movement to shift the position of the thermal element to vary the relation of the mercury to the switch contacts, said mercury switch being outside said casing, a housing for said casing and mercury switch, and means operable from the outside of the housing for moving said casing.

l5. A thermally actuated electric switch comprising a heat conducting plate adapted to contact with a heat radiant point, a heat responsive element disposed in close thermal relation to said plate, a casing cooperating with said plate to closely confine said heat responsive element, a mercury contactor switch exterior of said casing, means connecting said contactor switch with said heat responsive element` whereby operation of the former is controlled in accordance with the thermal conditions of the latter, a housing enclosing said mercury contacter switch, and means for adjusting the temperature at which the mercury contactor switch is operated by the heat responsive element, said means being operable without removing said housing.

16. A thermally actuated electric switch comprising a plate adapted to contact with a heat radiant point, a thermal responsive element disposed adjacent to said plate, an adjustable casing enclosing said thermal responsive element and in close thermal relation to said plate, an electrical switching means exterior of said casing, and means connecting said switching. means to said member, a casing cooperating with said heat conducting member to closely confine said heat responsive element, switching mechanism exteriorly of said casing, means connecting said switching mechanism with said heat responsive element whereby operation of the former is controlled in accordance with the thermal conditions of the latter, a housing enclosing said switching mechanism, and means for adjusting -the temperature at which the switching mechanism is operated by the heat responsive element, said means being operable without removing said housing.

18. In a thermostatically operated electric switch structure, the combination with a base plate constituting a mounting for the switch structure, of a thermal element, a heat conducting housing for said thermal element which is adjustably mounted upon said base plate, the said thermal element being in close thermal relation to said base plate and said housing, means for securing one end of said thermal element directly to said housing whereby heat is allowed to be conducted directly from said base plate to said thermal element through said heat conducting housing, an electric circuit breaker, means connecting said thermal element and said circuit breaker, and means accessible exteriorly o1' said heat conducting housing for adjusting in unison `the position of the said housing upon said base 

